1. Field of the Invention
Embodiments relate to production of composite silicon-carbon powders for use as anode materials in batteries.
2. Background of the Invention
Graphite powders often form anode material for lithium ion batteries. State-of-the-art graphite anode materials have nearly reached theoretical capacity of graphite powders (372 mAh/g). However, electronic devices are being designed to be smaller requiring both functionality and energy density power to continue to increase. In order to meet these demands, better anode materials for use in construction of lithium ion batteries need to be developed.
Lithium-alloying materials such as tin and silicon provide a higher lithium absorbing capacity than graphite. For example, silicon, which has an alloying capacity approximately 10 times that of carbon (4200 mAh/g), can alloy 4.4 lithium atoms to form SiLi4.4. However, the silicon alloying of lithium is accompanied by a significant volume expansion resulting in the process of lithium alloying and dealloying being irreversible. Consequently, plain silicon particle powders cannot be used as the anode material for lithium ion batteries. Manufacturing costs and performance issues limited usefulness of prior attempts to combine silicon and graphite.
Thus, there exists an ongoing need for an anode material for use in lithium ion batteries having improved capacity and cycling efficiency.